As a quadruped, there is an animal such as a racehorse or a riding horse bred (raised) in an environment in which a management system such as a health management is prepared. Hereinafter, the racehorse is exemplified.
One of the health management of a racehorse is checking a health condition of its legs. When a problem of inflammation, or the like occurs in its leg, it takes time to treat when a symptom progresses (worsens). In addition, when the problem occurs in its leg, the horse walks and runs while protecting the leg, and therefore, there is a concern that the problem also occurs in its other legs. For this reason, since the management of the health condition of a leg of the horse is considered important when breeding a racehorse, early detection of a problem of disease, injury, or the like is desirable.
The health condition of the leg of the racehorse is managed, for example, by having a veterinarian perform regular medical examinations on the leg of the horse. However, when the leg has an early mild inflammation, and the like, it is not easy to find the problem by only visual inspection or a palpation. For this reason, as an object such as supporting early detection of the problem of the leg, a method has been studied in which whether or not the leg has the problem is determined based on a balance between a right and left sides in respect to the body of horse.
In addition, as one of management methods of the health condition of the racehorse, there is a method in which the health condition is determined and managed based on output data of a sensor attached to the horse (for example, referring to Japanese Laid-open Patent Publication No. 2010-282456). In such a management method, the sensor such as an acceleration sensor, or the like is mounted to the leg or the neck of the horse, and the health condition is determined by comparing current operation data calculated based on measured data of the sensor with operation data of a normal state obtained in advance.